FACTBOX: Q&A on Asia's hand, foot and mouth epidemic

HONG KONG (Reuters) - Multiple epidemics of hand, foot and mouth disease have occurred in several countries in Asia in recent weeks, most notably in China where the disease has killed 34 children and Vietnam where is has killed 11.

Here are some questions and answers about the disease.

WHAT IS IT?

Hand, foot, and mouth disease (HFMD) is a common illness among infants and children. It is characterized by fever and a rash with blisters. One or two days after the fever begins, painful sores develop in the mouth. Other lesions typically form on suffers' hands and feet -- hence the name.

HFMD is often confused with foot-and-mouth disease in cattle, sheep and swine. Although the names are similar, the two diseases are not related at all and are caused by different viruses.

WHAT CAUSES IT?

A group of viruses from the group called enteroviruses. The most common cause is coxsackievirus A16. Sometimes, HFMD is caused by enterovirus 71 or other enteroviruses.

WHO IS MOST AT RISK?

HFMD occurs mainly in children under 10 years old, but also in adults. Infants, children, and adolescents are more likely to be susceptible because they are less likely than adults to have antibodies and to be immune from previous exposures to them.

HOW IS IT TREATED?

There is no vaccine or treatment for HFMD, although its symptoms can be treated to provide relief from fever, aches or pain from the mouth ulcers.

HOW DANGEROUS IS HFMD?

Usually not at all. HFMD caused by coxsackievirus A16 infection is a mild disease. Nearly all patients recover without medical treatment in 7 to 10 days. Complications are uncommon. Rarely, a patient with coxsackievirus A16 infection will also develop "aseptic" or viral meningitis, which is characterized by fever, headaches, and stiff neck or back pain, and may require the patient to be hospitalized for a few days.

WHAT'S BEHIND THE FATALITIES?

The current outbreak has led to 34 fatalities in China; mostly when linked with enterovirus 71. EV71 can also cause viral meningitis and, rarely, more serious diseases, such as encephalitis, or a poliomyelitis-like paralysis. EV71 encephalitis can be fatal. Cases of fatal encephalitis occurred during HFMD outbreaks in Malaysia in 1997 and in Taiwan in 1998.

HOW DOES HFMD SPREAD?